Fran P Laurel Springs , NJ December 15, 2014 Appliance: Frigidaire Microwave Hood Combo FPMV189KFB Frigidaire Microwave Fpmv189kfb: Frigidaire professional microwave not heating everything else was working ok eg (turntable and lights) unit had a loud humming sound when it stopped heating. How to replace Rectifier (Microwave High-Voltage Diode). Replaced the magnetron and high voltage capacitor. I tried replacing only the diode (rectifier) first with no luck. I hope this is helpful. 7 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 30-60 minutes